4 ms·
I see what you mean, but FWIW “fixed” doesn’t sufficiently constrain or describe it. For example, filling a rectangle with black or random pixels is a fixed alg
by dahart 10mo ago
I see what you mean, but FWIW “fixed” doesn’t sufficiently constrain or describe it. For example, filling a rectangle with black or random pixels is a fixed algorithmic sequence, same might go for in-painting from the background. The redaction output simply should not be a function of the sensitive region’s pixels. The information should be replaced, not modified.
- eurleif 10mo agoTo be pedantic, `f(x) = 0` is a function of x.
- dahart 10mo agoYeah, true. Is there a proper math term for a function of x that does not depend on x?
- MarkusQ 10mo agoThat's called a constant.
- dahart 10mo agoThat’s not quite the word I was looking for, since a function returning a random number isn’t a constant, and also doesn’t depend on it’s inputs.
- MarkusQ 10mo agoIf we're talking "proper math terms", if it "returns a random number" it isn't a function. In math, the value of a function can't change unless the arguments change. If you evaluate it repeatedly with the same argument(s) you'll always get the same result.
- dahart 10mo agoYes, you’re right, good point. Maybe there is no one good term for this case (but given the ocean of terminology, I’d be slightly surprised). ‘Not a function’ also isn’t the right term here because functions of x that returns a constant are okay - they just don’t depend on x. Hashed random functions are true functions but are designed to be non-invertible, so maybe non-invertible (or irreversible) is a decent single term for what @vunderba meant. Other terms that broach it might be ‘non-injective’ and ‘entropy-reducing transform’. I suspect those aren’t technically strong enough for the kind of information loss we need in this context.
- loeg 10mo agoA black redaction rectangle still leaks the dimensions of the occluded pixels, potentially revealing possible contents.